Question

Change into passive voice:1)They have informed him of his mother s death.

Answer 1

Heya , friend.
The answer to ur question is :
He was informed of his mother's death (by them).
Hope that it helps. ^_^

Answer 2

Answer:

He was informed of his mother’s death by them.

Explanation:  

Active voice is used for the sentences where, the action is performed by the subject present in the sentence and is expressed after a verb used.

The above answer is passive because, the subject has received the expressed action and the action in the sentence is focused more rather than the subject itself.

In passive voice, the doer of action remains unknown.